28 ideas
| 22024 | Fichte's subjectivity struggles to then give any account of objectivity [Pinkard on Fichte] |
| Full Idea: For Fichte 'subjectivity' came first, and he was then stuck with the (impossible) task of showing how 'objectivity' arose out of it. | |
| From: comment on Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 06 | |
| A reaction: The best available answer to this problem (for idealists) is, I think, Nietzsche's perspectives, in which multiple subjectivities are summed to produce a blurred picture which has a degree of consensus. Fichte later embraced other minds. |
| 15924 | Predicative definitions are acceptable in mathematics if they distinguish objects, rather than creating them? [Zermelo, by Lavine] |
| Full Idea: On Zermelo's view, predicative definitions are not only indispensable to mathematics, but they are unobjectionable since they do not create the objects they define, but merely distinguish them from other objects. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Shaughan Lavine - Understanding the Infinite V.1 | |
| A reaction: This seems to have an underlying platonism, that there are hitherto undefined 'objects' lying around awaiting the honour of being defined. Hm. |
| 17608 | We take set theory as given, and retain everything valuable, while avoiding contradictions [Zermelo] |
| Full Idea: Starting from set theory as it is historically given ...we must, on the one hand, restrict these principles sufficiently to exclude as contradiction and, on the other, take them sufficiently wide to retain all that is valuable in this theory. | |
| From: Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908], Intro) | |
| A reaction: Maddy calls this the one-step-back-from-disaster rule of thumb. Zermelo explicitly mentions the 'Russell antinomy' that blocked Frege's approach to sets. |
| 17607 | Set theory investigates number, order and function, showing logical foundations for mathematics [Zermelo] |
| Full Idea: Set theory is that branch whose task is to investigate mathematically the fundamental notions 'number', 'order', and 'function', taking them in their pristine, simple form, and to develop thereby the logical foundations of all of arithmetic and analysis. | |
| From: Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908], Intro) | |
| A reaction: At this point Zermelo seems to be a logicist. Right from the start set theory was meant to be foundational to mathematics, and not just a study of the logic of collections. |
| 10870 | ZFC: Existence, Extension, Specification, Pairing, Unions, Powers, Infinity, Choice [Zermelo, by Clegg] |
| Full Idea: Zermelo-Fraenkel axioms: Existence (at least one set); Extension (same elements, same set); Specification (a condition creates a new set); Pairing (two sets make a set); Unions; Powers (all subsets make a set); Infinity (set of successors); Choice | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Brian Clegg - Infinity: Quest to Think the Unthinkable Ch.15 |
| 13012 | Zermelo published his axioms in 1908, to secure a controversial proof [Zermelo, by Maddy] |
| Full Idea: Zermelo proposed his listed of assumptions (including the controversial Axiom of Choice) in 1908, in order to secure his controversial proof of Cantor's claim that ' we can always bring any well-defined set into the form of a well-ordered set'. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Believing the Axioms I §1 | |
| A reaction: This is interesting because it sometimes looks as if axiom systems are just a way of tidying things up. Presumably it is essential to get people to accept the axioms in their own right, the 'old-fashioned' approach that they be self-evident. |
| 17609 | Set theory can be reduced to a few definitions and seven independent axioms [Zermelo] |
| Full Idea: I intend to show how the entire theory created by Cantor and Dedekind can be reduced to a few definitions and seven principles, or axioms, which appear to be mutually independent. | |
| From: Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908], Intro) | |
| A reaction: The number of axioms crept up to nine or ten in subsequent years. The point of axioms is maximum reduction and independence from one another. He says nothing about self-evidence (though Boolos claimed a degree of that). |
| 13017 | Zermelo introduced Pairing in 1930, and it seems fairly obvious [Zermelo, by Maddy] |
| Full Idea: Zermelo's Pairing Axiom superseded (in 1930) his original 1908 Axiom of Elementary Sets. Like Union, its only justification seems to rest on 'limitations of size' and on the 'iterative conception'. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Believing the Axioms I §1.3 | |
| A reaction: Maddy says of this and Union, that they seem fairly obvious, but that their justification is of prime importance, if we are to understand what the axioms should be. |
| 13015 | Zermelo used Foundation to block paradox, but then decided that only Separation was needed [Zermelo, by Maddy] |
| Full Idea: Zermelo used a weak form of the Axiom of Foundation to block Russell's paradox in 1906, but in 1908 felt that the form of his Separation Axiom was enough by itself, and left the earlier axiom off his published list. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Believing the Axioms I §1.2 | |
| A reaction: Foundation turns out to be fairly controversial. Barwise actually proposes Anti-Foundation as an axiom. Foundation seems to be the rock upon which the iterative view of sets is built. Foundation blocks infinite descending chains of sets, and circularity. |
| 13020 | The Axiom of Separation requires set generation up to one step back from contradiction [Zermelo, by Maddy] |
| Full Idea: The most characteristic Zermelo axiom is Separation, guided by a new rule of thumb: 'one step back from disaster' - principles of set generation should be as strong as possible short of contradiction. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Believing the Axioms I §1.4 | |
| A reaction: Why is there an underlying assumption that we must have as many sets as possible? We are then tempted to abolish axioms like Foundation, so that we can have even more sets! |
| 13486 | Not every predicate has an extension, but Separation picks the members that satisfy a predicate [Zermelo, by Hart,WD] |
| Full Idea: Zermelo assumes that not every predicate has an extension but rather that given a set we may separate out from it those of its members satisfying the predicate. This is called 'separation' (Aussonderung). | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by William D. Hart - The Evolution of Logic 3 |
| 22017 | Normativity needs the possibility of negation, in affirmation and denial [Fichte, by Pinkard] |
| Full Idea: To adopt any kind of normative stance is to commit oneself necessarily to the possibility of negation. It involves doing something correctly or incorrectly, so there must exist the possibility of denying or affirming. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 05 | |
| A reaction: This seems to be the key idea for understanding Hegel's logic. Personally I think animals have a non-verbal experience of negation - when a partner dies, for example. |
| 13487 | In ZF, the Burali-Forti Paradox proves that there is no set of all ordinals [Zermelo, by Hart,WD] |
| Full Idea: In Zermelo's set theory, the Burali-Forti Paradox becomes a proof that there is no set of all ordinals (so 'is an ordinal' has no extension). | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by William D. Hart - The Evolution of Logic 3 |
| 18178 | For Zermelo the successor of n is {n} (rather than n U {n}) [Zermelo, by Maddy] |
| Full Idea: For Zermelo the successor of n is {n} (rather than Von Neumann's successor, which is n U {n}). | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Naturalism in Mathematics I.2 n8 | |
| A reaction: I could ask some naive questions about the comparison of these two, but I am too shy about revealing my ignorance. |
| 13027 | Zermelo believed, and Von Neumann seemed to confirm, that numbers are sets [Zermelo, by Maddy] |
| Full Idea: Zermelo was a reductionist, and believed that theorems purportedly about numbers (cardinal or ordinal) are really about sets, and since Von Neumann's definitions of ordinals and cardinals as sets, this has become common doctrine. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by Penelope Maddy - Believing the Axioms I §1.8 | |
| A reaction: Frege has a more sophisticated take on this approach. It may just be an updating of the Greek idea that arithmetic is about treating many things as a unit. A set bestows an identity on a group, and that is all that is needed. |
| 9627 | Different versions of set theory result in different underlying structures for numbers [Zermelo, by Brown,JR] |
| Full Idea: In Zermelo's set-theoretic definition of number, 2 is a member of 3, but not a member of 4; in Von Neumann's definition every number is a member of every larger number. This means they have two different structures. | |
| From: report of Ernst Zermelo (Investigations in the Foundations of Set Theory I [1908]) by James Robert Brown - Philosophy of Mathematics Ch. 4 | |
| A reaction: This refers back to the dilemma highlighted by Benacerraf, which was supposed to be the motivation for structuralism. My intuition says that the best answer is that they are both wrong. In a pattern, the nodes aren't 'members' of one another. |
| 4242 | Pure supervenience explains nothing, and is a sign of something fundamental we don't know [Nagel] |
| Full Idea: Pure, unexplained supervenience is never a solution to a problem but a sign that there is something fundamental we don't know. | |
| From: Thomas Nagel (The Psychophysical Nexus [2000], §III) | |
| A reaction: This seems right. It is not a theory or an explanation, merely the observation of a correlation which will require explanation. Why are they correlated? |
| 22018 | Necessary truths derive from basic assertion and negation [Fichte, by Pinkard] |
| Full Idea: Fichte thought that everything that involves necessary truths - even mathematics and logic - should be shown to follow from the more basic principles involved in assertion and negation. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 05 | |
| A reaction: An interesting proposal, though I am struggling to see how it works. Fichte sees assertion and negation as foundational (Idea 22017), but I take them to be responses to the real world. |
| 22064 | Fichte's logic is much too narrow, and doesn't deduce ethics, art, society or life [Schlegel,F on Fichte] |
| Full Idea: Only Fichte's principles are deduced in his book, that is, the logical ones, and not even these completely. And what about the practical, the moral and ethical ones. Society, learning, wit, art, and so on are also entitled to be deduced here. | |
| From: comment on Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Friedrich Schlegel - works Vol 18 p.34 | |
| A reaction: This is the beginnings of the romantic rebellion against a rather narrowly rationalist approach to philosophy. Schlegel also objects to the fact that Fichte only had one axiom (presumably the idea of the not-Self). |
| 22032 | Fichte's key claim was that the subjective-objective distinction must itself be subjective [Fichte, by Pinkard] |
| Full Idea: Fichte's key claim was that the difference between the subjective and the objective points of view had to be itself a subjective distinction, something that the 'I' posits. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 09 | |
| A reaction: This seems to lock us firmly into the idealist mental prison and throw away the key. |
| 22020 | We only see ourselves as self-conscious and rational in relation to other rationalities [Fichte] |
| Full Idea: A rational creature cannot posit itself as such a creature with self-consciousness without positing itself as an individual, as one among many rational creatures. | |
| From: Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794], p.8), quoted by Terry Pinkard - German Philosophy 1760-1860 05 n25 | |
| A reaction: [1796 book about his Wissenschaftlehre] This is the transcendental (Kantian) approach to other minds. Wittgenstein's private language argument is similar. Hegel was impressed by this idea (I think). |
| 22060 | The Self is the spontaneity, self-relatedness and unity needed for knowledge [Fichte, by Siep] |
| Full Idea: According to Fichte, spontaneity, self-relatedness, and unity are the basic traits of knowledge (which includes conscience). ...This principle of all knowledge is what he calls the 'I' or the Self. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Ludwig Siep - Fichte p.58 | |
| A reaction: This is the idealist view. He gets 'spontaneity' from Kant, which is the mind's contribution to experience. Self-relatedness is the distinctive Fichte idea. Unity presumably means total coherence, which is typical of idealists. |
| 22066 | Novalis sought a much wider concept of the ego than Fichte's proposal [Novalis on Fichte] |
| Full Idea: Novalis aimed to create a theory of the ego with a much wider scope than Fichte's doctrine of knowledge had been able to establish. ....Without philosophy, imperfect poet - without poetry, imperfect thinker. | |
| From: comment on Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Novalis - Logological Fragments I vol.3 p.531 | |
| A reaction: [in his 'Fichte Studies] Since this is at the heart of early romanticism, I take the concept to embrace nature, as well as creative imagination. There is a general rebellion against the narrowness of Fichte. |
| 22016 | The self is not a 'thing', but what emerges from an assertion of normativity [Fichte, by Pinkard] |
| Full Idea: Fichte said the self is not a natural 'thing' but is itself a normative status, and 'it' can obtain this status, so it seems, only by an act of attributing it to itself. ...He continually identified the 'I' with 'reason' itself. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 05 | |
| A reaction: Pinkard says Fichte gradually qualified this claim. Fichte struggled to state his view in a way that avoided obvious paradoxes. 'My mind produces decisions, so there must be someone in charge of them'? Is this transcendental? |
| 22019 | Consciousness of an object always entails awareness of the self [Fichte] |
| Full Idea: I can be conscious of any object only on the condition that I am also conscious of myself, that is, of the conscious subject. This proposition is incontrovertible. | |
| From: Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794], p.112), quoted by Terry Pinkard - German Philosophy 1760-1860 05 | |
| A reaction: [from the 1797/8 version of Wissenschaftslehre] Russell might be cross to find that his idea on this was anticipated by Fichte. I still approve of the idea. |
| 22061 | Judgement is distinguishing concepts, and seeing their relations [Fichte, by Siep] |
| Full Idea: For Fichte, to judge means to distinguish concepts from one another and to place them in relationship to one another. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Ludwig Siep - Fichte p.59 | |
| A reaction: This idea of Fichte's seems to be the key one for Hegel, and hence (I presume) it is the lynchpin of German Idealism. It seems to describe mathematical knowledge quite well. I don't think it fits judging whether there is a snake in the grass. |
| 22023 | Fichte's idea of spontaneity implied that nothing counts unless we give it status [Fichte, by Pinkard] |
| Full Idea: Fichte placed emphasis on human spontaneity, on nothing 'counting' for us unless we somehow bestowed some kind of status on it. | |
| From: report of Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Terry Pinkard - German Philosophy 1760-1860 06 | |
| A reaction: This idea evidentally arises from Kant's account of thought. Pinkard says this idea inspired the early Romantics. I would have thought the drive to exist (Spinoza's conatus) would make things count whether we liked it or not. |
| 22065 | Fichte reduces nature to a lifeless immobility [Schlegel,F on Fichte] |
| Full Idea: Fichte reduces the non-Ego or nature to a state of constant calm, standstill, immobility, lack of all change, movement and life, that is death. | |
| From: comment on Johann Fichte (The Science of Knowing (Wissenschaftslehre) [1st ed] [1794]) by Friedrich Schlegel - works vol 12 p.190 | |
| A reaction: The point is that Fichte's nature is a merely logical or conceptual deduction from the spontaneous reason of the self, so it can't have the lively diversity we find in nature. |